JPH06743Y2 - Fluid pressure confirmation sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a fluid pressure confirmation sensor for confirming whether fluid pressure is normal.

[Prior Art] A fluid pressure drive device such as a fluid pressure actuator generates a driving force according to the fluid pressure of a fluid supplied to the drive device, and thus it is necessary to set a fluid pressure suitable for the output of the drive device. is there. Therefore, normally, the fluid pressure on the secondary side is set by the pressure reducing valve whose set pressure can be adjusted so as to be constant regardless of the fluid pressure on the primary side.

However, in practice, the flow path between the pressure reducing valve and the drive device may be branched or blocked by various directional control valves such as a fluid-operated mechanical valve and a solenoid valve to cause the drive device to perform a predetermined work. Many. In this case, the movement of the internal mechanism of the directional control valve can be normally judged by the operation of the drive device, but when the drive device does not operate for some reason, it is determined whether the cause is the drive device or the directional control valve. Can not judge from.

Conventionally, for example, a semiconductor pressure sensor is known as a pressure detecting means.

That is, it is confirmed by the semiconductor pressure sensor that the fluid pressure is normally acting on the fluid flow channel, and that there is an abnormality in the driving device, and that the fluid pressure is not normally acting on the fluid flow channel. By confirming, it is possible to determine that the directional control valve is abnormal.

However, although the semiconductor pressure sensor has an advantage of being small and highly accurate, it has a problem that the cost is very high because a complicated electronic circuit is required for processing the output signal of the sensor.

The inventor of the present invention has proposed a fluid pressure confirmation sensor, which solves the above-mentioned problems, in Japanese Utility Model Laid-Open No. 1-75840.

As shown in FIG. 2, the previously proposed fluid pressure confirmation sensor has a housing 1 including a mounting screw 2a for a fluid pressure acting portion, a concave portion 3 and an inlet port 4 communicating with the fluid pressure acting portion and the concave portion 3. In the concave portion 3, a conductive material 7 which is always electrically insulating and changes to conductivity by compression, and a flexible sheet 6 on both sides thereof and a substrate 8 having a pair of electrodes 9 and 9 abutting the conductive material, Is installed, a fluid pressure is applied to the conductive material 7 through the flexible sheet 6, the conductive material 7 changes into conductivity, and the pair of electrodes 9, 9 are electrically connected. This confirms whether or not the fluid pressure is normal.

This fluid pressure confirmation sensor is small, highly accurate and inexpensive, and because the flexible sheet 6 covers the conductive material 7, it is possible to prevent deterioration of the conductive material 7 and malfunction of the sensor. However, there is a problem that it is difficult to increase the sensitivity of the sensor because the fluid pressure uniformly acts on the substantially entire surface of the conductive material 7.

[Problems to be Solved by the Invention] An object to be solved by the present invention is to provide a fluid pressure confirmation sensor which is small in size, has high accuracy and sensitivity, can easily process an output signal, and is inexpensive.

[Means for Solving the Problems] In order to solve the above problems, a fluid pressure confirmation sensor according to the present invention comprises a mounting portion for a fluid pressure acting portion, a recess having a locking portion at the tip, and the fluid pressure acting portion. A housing having an inlet port for communicating the recess, a flexible sheet sequentially inserted into the recess from the inlet port side, an indenter guide having a through hole in the axial direction, which is always electrically insulating and becomes conductive by compression. A peripheral edge of the substrate, comprising a conductive material, a substrate having a pair of electrodes and supporting the conductive material, and an indenter slidably mounted in the through hole for pressing a local portion of the conductive material. The indenter is brought into contact with the flexible sheet and the conductive material by the engagement of the locking portion with the locking portion, and the flexible sheet hermetically seals the inlet port side of the recess.

[Operation] When the flexible sheet, the indenter guide and the indenter, the conductive material, and the substrate are sequentially inserted into the recess of the housing and the peripheral edge of the substrate and the locking portion at the tip of the recess are locked, the indenter is pressed. Contacts the flexible sheet and the conductive material, and the flexible sheet hermetically seals the inlet port side of the recess.

In this case, since the locking force between the peripheral edge of the substrate and the locking portion does not act on the pressure receiving portion of the conductive material, the pressure detection accuracy does not deteriorate.

When the housing is attached to the fluid pressure acting portion by the attaching portion, if the fluid pressure acting on the indenter from the inlet port through the flexible sheet is normal, the indenter is pressed through the flexible sheet, As a result, the local part of the conductive material is compressed and becomes conductive, so that the pair of electrodes is electrically connected.

In this case, since the indenter compresses a local portion of the conductive material, compared to the case where a fluid pressure is applied to substantially the entire surface of the conductive material,
It is possible to increase the sensitivity of the sensor.

Further, since the fluid acting on the inlet port is hermetically sealed by the flexible sheet, it is possible to reliably prevent the deterioration of the conductive material and the malfunction of the sensor due to the fluid.

If the fluid pressure is not acting on the fluid pressure acting part, or if the fluid pressure is not acting normally, the conductive material does not change to conductivity, so there is electrical insulation between the pair of electrodes. There is.

Therefore, the reason why the drive device does not operate can be determined from the outside.

[Embodiment] FIG. 1 shows an embodiment of the present invention. A housing 21 of this fluid pressure confirmation sensor is provided with a screw 22a at one end for attaching to a fluid pressure acting portion such as a fluid pipe or a directional control valve. Each of the other ends is provided with a cover mounting screw 22b, which will be described later, and the middle portion is formed into a hexagonal shape for applying a spanner or the like.

The housing 21 has a recess 23 that opens on the screw 22b side, and a pressure fluid inlet port 24 is opened between the bottom surface of the recess 23 and the end surface on the screw 22a side. The flexible sheet 25, the indenter guide 26, the conductive material 27, and the substrate 28 are sequentially inserted, and the peripheral edge of the substrate 28 has a locking portion 23a at the tip of the recess.
Is locked to.

The flexible sheet 25 is made of a flexible and electrically insulating material, hermetically seals the peripheral wall of the recess 23, and is displaced toward the indenter guide 26 side when fluid pressure acts on the inlet port 24. The indenter guide 26 is made of a material that is not deformed by fluid pressure, is disposed in the recess 23, and has an axial through hole 26a at the center for guiding the sliding of the indenter, which will be described later.

The conductive material 27 contains a large number of metal particles, and is usually electrically insulating and changes to conductive when subjected to a compressive force,
The substrate 28 is made of a material having a relatively high strength that is electrically insulating and does not deform due to fluid pressure, and has a pair of electrodes 29, 29.
Are provided in the axial direction, and the tips of the electrodes 29, 29 are in contact with the end surface of the conductive material 27.

The indenter 31 slidably mounted in the through hole 26a of the indenter guide 26 is displaced by the fluid pressure acting from the inlet port 24 through the flexible sheet 25, and the conductive material 27 is locally compressed. Although the example shown in the figure is formed of a sphere, it is possible to intensively compress a local portion of the conductive material 27 such as a column or a stepped column with the diameter of the conductive material 27 reduced. , Can be any other shape.

Reference numeral 32 in FIG. 1 indicates electrodes 29, 29 screwed to the screw 22b.
Is the cover of.

Although not shown, the other ends of the electrodes 29, 29 are connected to a conductive material 27 such as a lamp or a buzzer through an appropriate power source.
Is connected to a device that can be confirmed to have changed to conductivity.

When the fluid pressure confirmation sensor is screwed to a predetermined fluid passage or a fluid pressure acting portion such as a directional control valve with a screw 22a, fluid pressure acts on the indenter 31 from the inlet port 24 through the flexible sheet 25. , When the fluid pressure is normal, the conductive material 27 is compressed by the indenter 31 to electrically connect the electrodes 29, 29,
When the fluid pressure does not act or is lower than normal, the conductive material 27 does not change to conductivity, so that the electrodes 29, 29 are electrically insulated. Therefore, it is possible to very easily confirm whether or not the fluid pressure is normal by detecting these states by an appropriate means.

The fluid pressure confirmation sensor can be made small and inexpensive, and the compression force for changing the conductive material to conductive can be adjusted by changing the amount of metal particles contained in the conductive material 27. The accuracy of pressure can be improved compared to a gauge.

Further, since the compressive force due to the displacement of the indenter 31 acts locally on the conductive material 27, it is possible to improve the sensitivity of the sensor as compared with the case where the compressive force acts on substantially the entire surface of the conductive material 27. it can.

Further, when the pressure fluid contacts the conductive material 27, the conductive material may be deteriorated or the sensor may malfunction, but since this is hermetically sealed by the flexible sheet 25, the moisture in the pressure fluid is It is possible to prevent deterioration and malfunction due to the above.

[Effects of the Invention] The fluid pressure confirmation sensor of the present invention confirms whether or not the fluid pressure is normally operating by the electrically conductive material that is electrically insulated and becomes electrically conductive by compression. The processing of the output signal becomes extremely easy, the fluid pressure confirmation sensor can be made small and inexpensive, and the accuracy can be improved as compared with the pressure gauge.

Further, by compressing the local part of the conductive material by the indenter inserted in the through hole of the indenter guide, the conductive material can be made conductive by a small fluid pressure, so that the sensitivity of the sensor can be improved.

Furthermore, since the conductive material is hermetically sealed with a flexible sheet, the conductive material does not come into contact with the pressure fluid.
It is possible to prevent deterioration of the conductive material and malfunction of the sensor.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of an embodiment of the present invention, and FIG. 2 is a vertical sectional front view of a proposed fluid pressure confirmation sensor. 21 ・ ・ Enclosure, 22a ・ ・ Screw, 23 ・ ・ Concave, 24 ・ ・ Inlet port, 25 ・ ・ Flexible sheet, 26 ・ ・ Indenter guide, 26a ・ ・ Through hole, 27 ・ ・ Conductive material, 28 ..Substrate, 29 .., electrode, 31 ..

Continuation of the front page (56) References JP-A-58-28635 (JP, A) JP-A-61-207939 (JP, A) Practical application Sho-49-33760 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A housing provided with a mounting portion for a fluid pressure acting portion, a recess having a locking portion at a tip thereof, and an inlet port for communicating the fluid pressure acting portion with the recess, and the recess from the inlet port side. A sequentially inserted flexible sheet, an indenter guide having a through hole in the axial direction, a conductive material that is normally electrically insulating and changes to conductivity by compression, and a substrate having a pair of electrodes and supporting the conductive material, and An indenter slidably mounted in the through hole for pressing a local portion of the conductive material, and the indenter is locked to a flexible sheet and a conductive material by locking the peripheral edge of the substrate and the locking portion. A fluid pressure confirmation sensor, characterized in that the flexible sheet hermetically seals the inlet port side of the recess while being brought into contact with.